The invention relates to an air treatment device for a commercial vehicle, with a housing which is designed for connection to an air dryer device via a quarter turn fastener.
Such air treatment devices of the type in question can be used in commercial vehicles, in particular trucks and tractors. The latter frequently have one or more compressed air consumers which have to be supplied with treated compressed air. Typical compressed air consumers are, for example, a compressed air braking system, a pneumatic spring system, or a parking brake system. A compressed air supply device which in particular has an air treatment system is provided for supplying the commercial vehicle with compressed air. The air treatment system is intended to provide, in particular, dried and purified air. For this purpose, an air treatment device is generally provided with an air dryer device which frequently also has filtering devices for filtering the air. In order to permit easy maintenance or replacement of the filters and, for example, of drying agent, an air dryer cartridge is generally used as the air dryer device which can be connected to the air treatment device or can be inserted into the latter. In order to connect the air dryer device to the air treatment system, a quarter turn connection or a quarter turn fastener can be used in this case. This connects the air dryer device to the air treatment device via a plug-in and turn connection. Examples of quarter turn fasteners for connecting air dryer cartridges to air treatment systems are described in laid open specification DE 10 2006 037 311 A1, to which reference is hereby explicitly made.
However, upon removal or exchanging of an air dryer device or air dryer cartridge, the air treatment device and therefore also the air dryer cartridge may still be pressurized. When a quarter turn fastener is unscrewed, the high pressure in the air treatment device may cause the quarter turn fastener to be released abruptly, thus putting nearby people and, in particular, the person removing the air dryer cartridge at risk. In addition, if the quarter turn fastener is not correctly installed, the quarter turn fastener may also be released automatically, which likewise results in considerable safety risks, for example in the driving mode.
The invention is based on the object of eliminating the prior art safety risks.
This and other objects are achieved on the basis of the air treatment device of the type in question in that a securing device which is fitted or is fittable to the housing is provided for securing the quarter turn fastener to the housing. In particular, the securing device can secure the quarter turn fastener or a quarter turn ring of the quarter turn fastener against rotation in an opening direction of rotation. By use of a securing device of this type, which is fastened or may be fastenable to the housing, the quarter turn fastener is prevented from being able to be undesirably or abruptly released under pressure. Furthermore, it is not necessary to drill sockets or holes into the quarter turn ring or the quarter turn fastener in order to receive the securing device, which preserves the structural integrity of the quarter turn fastener.
In particular, provision may be made for the securing device to be fastened or fastenable releasably to the housing, which facilitates the securing and releasing of the quarter turn fastener.
It is advantageous if, in a secured state of the quarter turn fastener, the securing device blocks rotation of a quarter turn ring of the quarter turn fastener in one direction of rotation. It is particularly advantageous in this case if, in the secured state, a lug of the quarter turn fastener butts against the securing device. Use is therefore made of already existing structures of a quarter turn fastener, such as the lug, and therefore no further machining steps are required on the quarter turn fastener in order to use the invention. The lug may be a quarter turn lug of the quarter turn fastener, in particular a quarter turn lug of a quarter turn ring; however, provision may also be made for a lug which does not serve as a quarter turn lug, such as a gripping projection, to be blocked by the securing device.
In one embodiment, provision is made for the securing device to be designed as a closure screw. A closure screw provides reliable support and good securing of the quarter turn fastener. Use may also be made of further forms of securing devices, for example the securing device may be designed as a split pin or bolt.
It is particularly advantageous if the closure screw has a closure screw head which, in a secured state, is arranged in such a manner that it blocks movement of a lug of a quarter turn ring of the quarter turn fastener in one direction of rotation. In particular, provision may be made for the closure screw head to butt against the lug in a secured state. A closure screw head can easily be formed so as to block the lug at least in one direction of rotation.
In a preferred development, a bore for receiving the securing device is provided in the housing. The bore may be designed in particular as a threaded bore in order, for example, to receive a closure screw. Secure holding of the securing device in the housing is provided by such a bore.
In this case, it is particularly expedient if the bore reaches into an interior space of the air treatment device, which interior space is pressurized during operation. The securing device then advantageously includes a seal which, in the fitted state, seals the interior space of the air treatment device against a loss of compressed air. It is also advantageous in this connection if, when the securing device is not fitted, the interior space is not sealed. In this case, the air treatment device can therefore not supply the compressed air consumer with compressed air, since pressurized air escapes to the outside via the connection of the interior space to an external region. If the air dryer device is not correctly fitted and secured, the air treatment device therefore cannot be pressurized, which minimizes safety risks associated with the operation of an incorrectly fitted air treatment device.
It is of particular advantage if the securing device has one or more venting ducts. The latter are expediently arranged in such a manner that they permit venting of the air treatment device when the securing device is released. The effect achieved by this is that, whenever there is still pressure in the air treatment device during the initial releasing operation of the securing device, this pressure can escape via the venting duct or the venting ducts. If the release operation is then continued, the air treatment device is no longer pressurized, as a result of which the securing device can be safely released further without the risk of being removed abruptly by high pressure.
Provision may be made for the securing device to have a predetermined breaking point. The latter may result in breaking of the securing device if the securing device is not properly fitted. The securing device is therefore prevented from being fitted incorrectly and with excessive force. It is particularly expedient in this case for a predetermined breaking point of this type to result in a break in the region of the venting duct or the venting ducts, thus preventing the air treatment device from being pressurized when the securing device is broken if the latter can no longer reliably secure the quarter turn fastener. For this purpose, the breaking point should be arranged in such a manner that the venting duct is opened outward by breaking of the predetermined breaking point.
In one embodiment, provision may be made for the housing to have a guide for the securing device. This facilitates the installation of the securing device. In particular, the securing device may be a trough. As a result, the securing device can be easily guided and a fitter's fingers holding the securing device can be easily introduced. Provision may also be made for the guide to completely surround an end region of the securing device and thus to stabilize the securing device during the fitting thereof. In particular, a guide of this type may be a bore. As an alternative, a guide which has both a trough and an element which completely surrounds an end region of the securing device may be provided.
In a particularly preferred development, the housing has a stop for a lug of the quarter turn fastener, said stop blocking rotation of a quarter turn ring of the quarter turn fastener in one direction of rotation. In particular, it is expedient if the stop blocks the rotation of the quarter turn ring in the other direction of rotation than the securing device. The stop can block any lug of the quarter turn fastener or of the quarter turn ring, in particular the lug blocked by the stop may be identical to a lug blocked by the securing device or else may be a different lug of the quarter turn fastener.
It is very particularly advantageous if, in a secured state, a lug of the quarter turn fastener is arranged between the stop and the securing device. For this purpose, the distance between the stop and the securing device may in particular be designed in such a manner that the lug fits precisely in between. Therefore, a precisely defined position of the quarter turn fastener can easily be set. In particular, an incorrect position of the quarter turn fastener and safety risks associated therewith can be avoided. It is particularly expedient that, if the lug does not bear correctly against the stop, the securing device cannot be fastened to the housing, for example, because the lug covers a bore for receiving the securing device if the latter is not correctly positioned.
It is self-evident that any suitable type of quarter turn fastener may be used within the context of this description. It can optionally be ensured by mechanical measures, for example by suitable guidance of the quarter turn ring, that the components of the quarter turn fastener, and in particular the quarter turn ring, can assume the correct position, for example in such a manner that a quarter turn lug can be arranged between the stop and the securing device. Measures suitable for purposes of this type are presumed to be known to a person skilled in the art. It is also contemplated within the context of the invention that the air dryer device is covered by an additional, separate cartridge housing which can likewise be connected to the housing by the quarter turn fastener. It is also possible for the quarter turn ring to be fixedly connected to a housing of the air dryer device or to a cartridge housing of this type. Of course, the quarter turn ring may also be designed as a separate component.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.